Sonco Tube


Triple Coat Galvanized Steel Tubing

Triple Coat Advantages Are More Than Skin Deep

Triple Coat is our superior, triple-layer rust and corrosion resistant product protection that has been the standard of excellence and the product of choice for outdoor structures for over 15 years.

Triple coated galvanized steel tubing is given superior corrosion resistance by our patented, in-line triple coat process. Coatings of zinc and chromate are applied, then a clear polymer topcoat seals the surface. The result is unmatched, long-lasting rust and corrosion protection. Triple coat provides a bright, smooth and uniform surface, and retains its attractive appearance for an extended period. Aluminum turns a dull, dark gray as it ages.


Triple Coat Can Make Structures 60% Less Costly

Galvanized steel’s advantages over aluminum add up. Lower material cost, less material required per structure, and less fabrication expense add up to a compelling cost argument in favor of triple coated tubing as the material of choice for outdoor structures. And the much-reduced risk of post-installation failure due to welding and wind, snow, or ice loading is triple coat’s “insurance policy” against expensive repair or replacement in the future. Also, the use of steel reduces theft and vandalism of structures… the scrap value of aluminum is more than 10 times that of steel.

Advantage: Greater Strength

Triple coated galvanized steel’s superior strength is the key to its advantage over aluminum yielding greater structural integrity and requiring fewer linear feet of material per structure. In turn, these advantages translate into longer life and lower costs for outdoor structures.

You’ll Need Less Steel

Triple coat’s higher strength permits the use of smaller sizes and/or lighter walls to achieve the desired design performance. Less triple coated tubing is required than aluminum for any given outdoor structure. Less material and galvanized’s lower material cost (approximately 50% savings vs. aluminum) give triple coat a compelling advantage over aluminum.

Advantage: Superior Fabrication

A comparison of the requirements for fabricating outdoor structures of Gatorshield® and aluminum reveal major advantages for triple coat:

  • Triple coated galvanized ductile steel tubing withstands the bending and forming required for custom awning designs, recreational equipment, etc. Common tempers of aluminum, however, continue to age-harden while in storage and can break during any fabrication process, causing costly scrap losses.
  • Aluminum loses approximately 50% of its strength in the weld area, which could cause post-installation failure if welds are not located in low-stress areas of the structure during its design. In addition, welding of aluminum, or using aluminum electrodes, which contain magnesium, can result in unsightly black deposits.
  • Steel structures require significantly fewer welds as indicated in the table below and the engineering drawings to the left. The result is lower welding labor costs for triple coat structures. Welding triple coated galvanized steel also requires less expensive equipment and materials. And, unlike aluminum, galvanized can be easily welded in the field.
  • Triple coat steel tubing is easily and less expensively painted or powder-coated than aluminum, offering variety in color, texture, and sheen to enhance design possibilities and aesthetic appeal. Because the third coat has the same paint chemistry and surface consistency as costly primers, finish adhesion is excellent, providing a long-lasting, attractive appearance.

Advantage: Unmatched Durability

The higher rigidity of triple coated galvanized  structures means less bowing and deflection than aluminum structures under identical load conditions. This translates to a much more stable installation, with far less chance of damage to the fabric covers, graphics, and backlit illumination equipment of custom awnings and the roofs of structures. The superior hardness makes framing and support structures much more resistant to everyday dings and dents. And its approximately 30% greater load-carrying capacity than aluminum, size for size, is dramatically revealed as a triple coated galvanized steel’s advantage in the test below which was conducted by Construction Research Laboratory, Inc. of Miami, an independent testing laboratory.

Wind Comparison

Both test awnings were 15’0″ wide by 3’6″ high by 8’0″ deep and identically attached to a supporting back wall structure. One awning frame was fabricated of triple coat 1.050″ OD by 14 gauge and 0.815″ OD by 15 gauge welded steel tubing; the other from Schedule 40 1.050″ by 12 gauge and 0.840″ OD by 12 gauge 6061-T6 extruded aluminum pipe. Identical awning material was used for each. And each awning was subject to wind speeds increased in 10mph increments.

Triple Coating Process

Triple coating is the superior method of galvanizing steel tubing. It begins with flat strip steel, which is then cold-formed and electric-resistance or induction welded. After welding, the tube receives a triple layer of protection-zinc, conversion coating, and a clear polymer top-coat – all applied in-line to assure a uniform coating. The result is a smooth, shiny end product appearance that is unmatched in terms of strength and durability.

Triple coat tubing exhibits greater corrosion resistance because of the synergism created between the coatings; the conversion coating passivates the zinc to slow down the white rust growth process, and the clear top-coat then “seals in” the protection.

The triple coat corrosion provided by the in-line manufacturing processes has never been equaled. This triple-layer protection (zinc, conversion coating, and clear organic polymer) provides a smooth, shiny product appearance that is unmatched in terms of strength and durability.

The Triple Coat Process Inherent Advantages…

  • The cold-forming and quenching process creates greater yield and tensile strength than competitive product alternatives.
  • The tube is welded prior to the application of coating; thus the weld area is as protected from corrosion as the rest of the tube body.
  • Triplecoated tubing exhibits greater corrosion resistance because of the synergism created between the coatings; the conversion coating passivates the zinc to slow down the white rust growth process, and the clear top-coat then “seals in” the protection.
  • The clear third coating also acts as a primer for painting or powder coating. Extensive pre-cleaning is unnecessary, and excellent adhesion is achieved, even at high baking temperatures.
  • Powder coating over our galvanized substrate provides substantial corrosion resistance superiority over powder coating a raw/uncoated substrate. Powder coating over a galvanized surface provides corrosion protection 5-6 times longer than the same over a raw or bare surface.
  • Welding triple coat is easily done in the exact same manner as welding bare steel. Our zinc coating contains the lowest lead content achievable (99.9% pure zinc, average 13 ppm), so lead oxide fumes generated during welding are kept to an absolute minimum. Hot-dip galvanized products usually contain up to .5% lead (5000 ppm).
  • In-line galvanized products can be easily fabricated…bent, swaged, wall-to-wall flattened…without deformation of the triple layer of protection. Competitive products tend to flake and chip during fabrication.

Looking for more on the triple coat process? Contact one of our Sonco Tube professionals who are standing by to provide additional information or to provide a free quotation for your next tubing project.

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